Help Wanted! - HTTP Request Headers

[ivan-sincek]

I would grately appreciate some kind of [official] technical documentation about the following HTTP request headers:

Base-URL
Proxy
X-Forward
X-Forward-For
X-Forwarded-For-Original
X-HTTP-DestinationURL
X-Originally-Forwarded-For
X-Override-URL

Please do not post links to wordlists or other similar 403 bypassing tools!

I am interested in technical documentations such as these:
developer.mozilla.org/en-US/docs/Web/HTTP/Headers
developers.cloudflare.com/fundamentals/reference/http-request-headers